256 ANNUAL REPORT SMITHSONIAN INSTITUTION, 193 9 



We know, thanks to archeological research, of complex human civili- 

 zations antedating the official creation of the world; and we know, 

 through geological research, of animals and plants that postulated 

 the earth in eras a thousand times more remote. We know, but we 

 cannot truly comprehend. 



Although we must stand bewildered before the actual figures of geo- 

 logical time, more hopelessly than before those of cosmic space, there 

 is no serious difficulty in appraising relative time values. A million 

 years may be inconceivable, but they are obviously fewer than ten 

 million or a hundred million. We can mentally dispense with the 

 ciphers, and reduce the totals within the limits of our understanding. 

 So that if we estimate the duration of mankind at 1,000,000 years, 

 and that of the Cenozoic era (the "age of mammals") up to the 

 present at 60,000,000 years, the ratio of 1 to 60 is a true and intelligible 

 expression of the data. Whether we give credence to the estimates of 

 the length of preceding eras or not, we can readily understand that 

 they were collectively vastly longer than the Cenozoic. And who 

 shall say what vistas of time are behind and beyond the mists of 

 the pre-Cambrian ? Without pretending to ascribe to geologists an 

 abnormal share of the attributes of Deity, it is within the truth to 

 say that they think in terms of time where "a thousand ages" are lost 

 in the total. 



The calculations of astronomers and physicists have, of course, a 

 profound interest for geologists, and we may be gratified if their re- 

 sults accord with ours. But we must be forgiven if we regard them 

 as giving but uncertain confirmation, or negligible denial, of our own 

 deductions. Too often in the past century did the physicists attempt 

 to limit the duration of the world, and of the solar system, within 

 impossibly small scope, basing their conclusions on the elusive and 

 superficially convincing principles of mathematics. Doubtless their 

 arithmetic was beyond cavil ; but the premises were inevitably incom- 

 plete and even inaccurate. The hoary imposture of the accuracy of 

 the "exact" sciences still deludes mankind, through the wildly illogi- 

 cal belief that a rigidly logical argument must reach a correct result 

 whatever errors may have existed in the premises on which it is based. 

 Nevertheless, however askance we may look at the current theories 

 of astrophysics, we can recognize with satisfaction, that their bearing 

 on time is consistent with the conception of the world's duration 

 deduced from geological facts. 



Three considerations that are inspired by our present knowledge of 

 geological history may be emphasized here. In the first place, the 

 human race, though of far greater antiquity than our forebears 

 taught, has existed for a minute fraction of the time during which 

 the world has been essentially like it is today. Indeed, the "human 



